If you thought the title to this section had Hollywood disaster movie connotations, you would definitely be right! Many paleontologists believe that a shocking 99% of all species of life that have ever existed are actually extinct today. At this point, it is important to acknowledge the fact that we are talking about entire ‘species’ of animals here.
This shocking statistic comes from our study of fossils and the fact that although we estimate there to be millions of species on our planet today, these only represent around 1% of all of the species that have existed in the past. So, since life really started to take off after the Cambrian explosion 545 million years ago, our planet has seen the vast majority of these wiped out throughout its history.
We have a fairly good idea of when many species were exterminated in history and these have been given the rather frightening title of ‘mass extinction events’. Whilst some species of animals will always become extinct even when the Earth is going through a stable period, it is the fact that there have been 5 massive events over the last half a billion years that we believe have been responsible for most of the casualties of these unfortunate species.
These mass extinction events are believed to have occurred when the planet has seen incidents such as rapid and significant warming or cooling of the global climate – which has happened in a cyclical pattern throughout our planet’s history; perhaps even through increased volcanic activity; but the biggest cause here has probably come from the fact that our planet has been hit by huge asteroids that would have plunged the Earth into darkness for centuries afterwards, if the poor unfortunate life was not obliterated as a result of the initial impact of this huge chunk of space debris.
The 5 mass extinction events that are currently known about wiped out whole orders and families of species at a time, and perhaps the best known of these, is the mass extinction event that occurred 65 million years ago. This was thought to be responsible for wiping out all of the dinosaurs and it is important to note that we are talking about many thousands of species of this type of animal at that time. This event is believed to have occurred when a huge asteroid crashed into the Earth in the region we now know of as the Gulf of Mexico.
Mass extinction events are an absolute fact of life when it comes to the planet Earth. The most worrying thing is that we now believe that we are currently living through the 6th event in our planet’s history, as literally thousands of species of animals have been lost at an alarming rate over the past decades. This is all connected with one single species of animal; one that has only been around for a mere 200,000 years, but is easily the most destructive our planet has ever known. That species is known as Homo sapiens – also known as us!